The present invention relates to aqueous mixtures of additives that provide improved adhesion of adhesives to glass and improved dispersion of fibers and particles.
Various fibrous or particulate materials, including glass, glass microspheres, glass filament, glass powders and especially chopped fiberglass, are used in various products as a filler to reduce weight or add strength to products. Examples of these applications are the production of nonwoven mats, filter media, gaskets, roofing mats, roofing shingles, cementicious building materials, molded fiberglass parts, and automotive and marine body fillers.
Often fiberglass is used in an aqueous system, and during use these fibers can settle out of or float on top of liquid solutions, which leads to problems in production. Many fibers, including glass and especially fiberglass, are not normally wetted by water very well and have the tendency to clump together, or not disperse well, when added to an aqueous system. Surfactants are used to enable liquids to wet the fibers by lowering the surface tension, but the surfactants may not suspend or separate the individual fibers. Thickeners, for example, guar gum, are used to increase the viscosity of a water/fiberglass system to help suspend the fiberglass. Frequently, constant agitation and/or high shear is applied to keep the fiberglass homogenously suspended.
The production of a homogenous suspension of fiber in water will improve the handling and performance of fiber, allowing more uniform coverage and accurate placement of fiber in applications where fiber is used to give strength and fill to products. Reducing the need for continuous mixing or high shear is also beneficial from an energy and convenience standpoint.
The invention disclosed herein includes a dispersion additive system that promotes the wetting of glass, whether in fiber form, particulate form, or other form, e.g., plate glass, by liquids. When applied to fiber glass, it helps separate the fiber bundles into individual fibers without the need for high shear and suspends the separated individual fibers. The unbundling and dispersion of the fiber filaments by these additives leads to good infiltration of resins into the fiber as well as improved adhesion of the resin to the fiber. Good contact, infiltration, and adhesion of resins to glass promoted by these additives leads to a stronger bond between the resin and glass and increases the strength of the glass/resin system. When applied to glass in other forms, such as plate glass, the materials of the present invention promote adhesion of resinous coating materials to the glass.
The present invention, therefore, in one aspect, solves the problem of providing improved dispersion of fibers or particles, e.g., chopped fiber glass, which may otherwise need high shear or continuous stirring to disperse, separate and suspend them. It accomplishes this by chemically dispersing the glass fibers. The invention also modifies the surface of the glass, in whatever form, to improve wetting and adhesion.